Roofing materials are susceptible to infestation of various microorganisms, including fungi, bacteria and blue-green algae, which result in undesirable dark streaks on roofing surfaces after only a few years in service. Previous solutions that rely on applications of organic or inorganic biocides, metal strips, or metal oxides to inhibit or delay the microorganism infestation are only effective for a few years, usually less than ten years.
Accordingly, there is a need for an improved biocidal roofing material.